Middle and high school programs targeting social influence factors and social skills development constitute the predominant strategy for preventing tobacco and alcohol use. Recent efficacy studies of such school-based interventions report difficulty in achieving sustained effects on tobacco use, and difficulty in having any effect on alcohol use. Based on the premise that earlier intervention is needed to prevent use, the proposed project aims to: (1) test hypotheses regarding developmental precursors that increase children's risk of tobacco and alcohol use, and, by doing so, identify targets for an early prevention program; (2) develop and test intervention components that would comprise an early prevention program. A four year panel study will be conducted to test hypotheses linking childhood socialization variables, i.e., general parenting practices, tobacco and alcohol specific socialization, and child competency development, to the onset and persistence of tobacco and alcohol use by children. Two panels, each with 600 children, will be followed. One panel will be followed from grades 3 through 6 (ages 8 through 11); the other will be followed from grades 5 through 8 (ages 10 through 13). At baseline and at three annual follow-up assessments, survey data will be collected from the children, their parents and their teachers. Measures of childhood socialization variables, child competency development, and child use of tobacco and alcohol will be obtained at each assessment. Results of the panel study will indicate to what extent, and in what manner, early intervention in family socialization processes can be expected to reduce children's risk of tobacco and alcohol use. Program development work will begin during the third year of the project, when a comprehensive framework for an early prevention program targeting childhood socialization processes will be developed. This framework will specify the behavioral objectives, educational components, implementation system, and evaluation criteria for the intervention. Then, prototypes of intervention components will be developed, such that intervention materials and activities will be designed to meet the objectives specified in the framework. The goal of the program development phase of the project is to produce an intervention which has been theoretically and empirically derived, and which has undergone sufficient field testing to be ready for full-scale implementation and efficacy testing.